A federal official admitted mistakes were made in a Senate hearing on the midair collision at Ronald Reagan National Airport that killed 67 people, as lawmakers continue to press top aviation and safety officials for answers on the congested airspace.

Federal authorities detailed the findings of the National Transportation Safety Board‘s report, which was released on March 11, on why a military helicopter and a plane that departed from Wichita, Kansas, carrying elite figure skates and families crashed into each other and fell into the Potomac River.